Mulch provides a multitude of benefits

GARDENING

June 22, 1991|By Art Kozelka | Art Kozelka,Chicago Tribune

Put mulches to work for you and discover how they can encourage healthier growth of flowers, vegetables and other plants, add aesthetic appeal to landscaped areas and significantly ease tedious maintenance chores.

Although mulching is good for the garden year-round, its function during the summer is especially beneficial. It helps to:

* Slow evaporation on sizzling summer days and thus conserve water.

* Inhibit weeds, thereby reducing cultivation to a minimum.

* Stabilize soil temperature.

* Improve the quality of the soil.

Mulches can be described as any kind of material used to cover the soil. Indeed, stones, wood planks, discarded rugs and even newspapers have been used.

But there always has been a decided preference for organic mulching substances that decompose to improve the soil texture and drainage. Among these are such common materials as dried grass clippings, ground corn cobs, buckwheat hulls, clean straw, cocoa and pecan hulls and shredded hardwood bark. One's choice of materials is likely to be influenced by their availability locally, as well as where they are to be used.

Most conveniently available, of course, are grass clippings, now widely banned at overburdened landfills. Turf experts urge leaving short clippings on the lawn as a beneficial mulch. An alternative is to rake up the clippings and use them as a mulch elsewhere. If this is done, allow the clippings to dry for a day or more so they will not generate heat when applied.

A substantial mulch will effectively slow evaporation and protect tender roots from an overheated soil, which can adversely affect such plants as impatiens, geraniums, roses, begonias, clematis and many other annuals and perennials, as well as some vegetables.

Tomatoes, for example, often develop a major problem known as blossom-end rot, which shows up as black spots opposite stems and is caused by abrupt changes in moisture content of the soil. A good mulch tends to prevent this while also keeping the tomatoes clean and free of blemishes caused by splattering when rain falls on bare soil.

While grass clippings or straw may be fine for the strawberry patch or vegetable plot, they are hardly appropriate for ornamentals such as roses, trees, shrubs or in beds of flowering plants. Here more decorative materials such as bark can do much to enhance the plantings.

Bark is available in a variety of sizes, textures and colors, giving the gardener a choice for specific decorative effects. It decomposes slowly, with the resulting humus enriching the topsoil beneath it, and will endure longer than other organic mulches.

As for control of pesky weeds, mulching can be effective without resorting to herbicides. An adequate mulch will deprive weed seeds and seedlings of the sunlight they need to grow. An isolated weed that manages to poke through is easily yanked out with its roots from soil kept moist by the mulch.

Before applying any mulch, cultivate the soil thoroughly to remove all existing weedy growth. This is important because weeds that have attained substantial growth, as they already have this season, may be vigorous enough to penetrate a mulch.

Earliest possible application of mulches, therefore, makes good sense, particularly in beds of roses where it is easier to work before the advancing growth of thorny canes can be a hindrance.

After weeds are eliminated, work a thin layer of the mulching material into the soil. Then spread the rest of the material on this foundation to any desired thickness. Ordinarily a 2-to-4-inch blanket of mulch is sufficient to inhibit weeds and sustain soil moisture.

When it's necessary to water mulched plants, make sure the water reaches the deepest roots for the longest-lasting benefit. Check the penetration by pushing aside some of the mulch and probing into the soil to determine whether the water has gone deep enough.

Avoid mere "sprinkling" of mulched areas, however often, as this will induce short root growth that may not carry the plants through extended dry periods. A much better way to water is to use soil soakers, which allow the water to seep out gently along their length without eroding the mulch.